[Dysnatremias - concepts and clinical work-up].

Area of Science:

• Physiology and Pathophysiology of Body Fluids
• Endocrinology and Metabolism
• Nephrology

Context:

• Osmotic gradients across cell membranes drive water movement, necessitating intact osmoregulation for cellular integrity.
• Sodium (Na+) is the primary extracellular cation, critically determining extracellular fluid (ECF) and plasma osmolarity.
• Imbalances in water and electrolyte concentrations lead to hyponatremia (low Na+) or hypernatremia (high Na+).

Purpose:

• To provide a pathophysiology-oriented approach to managing dysnatremias (hyponatremia and hypernatremia).
• To outline therapeutic strategies based on the type, duration, symptoms, and volume status of dysnatremic patients.
• To discuss the fundamental concepts in the clinical management of sodium balance disorders.

Summary:

• Hyponatremia results from excess electrolyte-free water decreasing osmolyte concentration; hypernatremia stems from a free water deficit increasing osmolyte concentration.
• Treatment for hyponatremia includes water restriction, hypertonic infusions, urea, V2 receptor antagonists, and SGLT2 inhibitors.
• Hypernatremia management involves administering electrolyte-free water or hypotonic sodium solutions, guided by the patient's volume status.

Impact:

• Facilitates accurate diagnosis and tailored treatment of sodium balance disorders for improved patient outcomes.
• Empowers clinicians with a structured approach to managing complex electrolyte disturbances.
• Highlights the importance of understanding osmotic physiology in clinical practice.